Background: Heavy vehicle drivers are at risk of musculoskeletal disorders due to risk factors that are present in their job. The aim of this study was to investigate the prevalence and risk factors of musculoskeletal disorders in bus and truck drivers. Methods: This cross-sectional study was carried out on 275 bus and 272 truck drivers using random sampling method. Nordic Musculoskeletal Questionnaire (NMQ) was used to assess the prevalence of musculoskeletal disorders. All analysis was performed by R software. Results: The mean age of bus and truck drivers was 42.74 and 39.76 years, respectively. In total, 26.9% of bus drivers and 31.6% of truck drivers reported pain in one of their nine body parts at least once during the previous year. The waist and knee with a prevalence of over 17% had the highest frequency. The results showed high frequency of exposure to vibration and smoking in the both groups. About 61% of drivers in both groups reported lack of job satisfaction. Conclusion: The prevalence of musculoskeletal disorders, especially low back pain in drivers was high. It seems that the development of an appropriate program for improving occupational health in drivers especially ergonomic interventions is necessary.